Spot-welding apparatus



Feb. 26, 1929. 1,703,541

w. H. PIERsoN SPOT WELDING APPARATUS Filed NOV. l, 1926 Patented Feb.26, 1929.

UNITED STATES PATENT OFFICE.

WILLIAM H. PIERSON, OF DETROIT, MICHIGAN, ASSIGNOR T0 BRIGGS MANUFACTUR-ING COMPANY, OF DETROIT, MICHIGAN, A. CORPORATION 0F MICHIGAN.

SPOT-WELDING APPARATUS.

Application led November 1, 1926. Serial No. 145,537.

This invention relates generally to welding apparatus and consists ofcertain novel features of construction, combinations and arrangements ofparts as will be more fully described and particularly pointed out inthe appended claims.

I-n the accompanying drawings:

Figure 1 is a side elevation of an appara tus embodying my invention. v

Figure 2 is an enlarged fragmentary side elevation thereof.

Figure 3 is a top plan view of the construction shown in Figure 2.

'Figure 4 is a detail elevation of the upstanding arm of the worksupport.

Figure 5 is a detail elevation of the bearing seat.

Figure 6 is a fragmentary elevation of the movable electrode supportingarm and showing the adjustable electrode rod applied thereto.

Figure 7 is a detail elevation of the sleeve used to insulate theelectrode supporting arm and the work support from the main frame of theapparatus.

Figure 8 is a fragmentary vertical sectional view taken on the line 8--8of Figure 1.

Referring now to the drawings, 1 is a work support, and 2 and 3respectively are welding electrodes of a welding apparatus embodying myinvention. As shown7 the work support 1 has an upstanding arm 4 thatconstitutes a seat for the work, and has a substantially horizontal arm5 that is rigidly securedto a saddle 6 on the main frame 7 of theapparatus. Preferably this horizontal arm 5 is yformed of two sections 8and 9 respectively that are insulated from each other by a suitableflanged sleeve 10 of non-conducting material, while the upstanding arm 4is preferably rigid with the `hori'zontal arm 5 but is provided at itsupper end with an upwardly opening recess 11 in which va seat 12 for thework is adj ustably mounted. As shown, this seat 12 rests upon a ball 13in the recess 11 and has a fiat upper face14 upon which the work isadapted to rest. Thus the seat 12 may adjust itself upon the ball 13 sothat theiat face 14 will assume the proper angular position with respectto the arm 4 to provide the proper bearing for the work, and thereby`prevent the work from being dented or otherwise damaged when applied tothe seat.

In the present instance the welding is effected indirectly through thework, hence both electrodes 2 and 3 are preferably carried by'and aremovable with a common supportmg arm 15 which in turn is pivotallymounted upon the main frame 7 of the apparatus. As shown the electrode 2comprises an apertured block and is suitably connected ,to the lower endof a vertically adjustable rod 16 carried by the outer end 0f the arm15. Preferably this rod 16 passes freely through the arrn 15 and isinsulated therefrom by a sultable flanged sleeve 17 of non-conductmgmaterial. A nut 18 is secured upon the rod 16 above the arm 15 to limitthe downward movement of the rod. while a suitable washer 19 also ofinsulating matcrial is fastened 1 upon the rod 16 below the arm 15 tolimit the upward movement of ered position. However the arrangement issuch that this spring will permit the electrode 2 to yield slightly tocompensate for work of varying thicknesses. Preferably the electrode 3is pencil like in form and is rigidly secured in the arm 15 adjacent tothe rod 16. To provide an efficient construction the welding point 21 ofthis electrode 3 is removable and preferably terminates a slightdistance above the lower work engaging face of the block electrode 2.

Any suitable means such as the electrical conductors 22, 23 and 24respectively may be used to carry the current from the usual transformerin the frame 7 to the electrodes 2 and 3 respectively. As shown theconductors 22 and 23 preferably lead from the saddle 6 and areterminally connected to the electrode 2, while the conductor 24 leadsfrom the transformerin the frame 7 to -a suitable collar 25 on thepivotally mounted arm 15. Preferably this collar 25 is insulated fromthe innerpivoted end portion 26 of the arm i -by means of a suitableflanged collar 27 of this pedal 33 is actuated the arm 15 will move' thearm 15 and electrode 3 to the point 21, and will flow from theconductors 22 and 23 direct into the blockelectrode 2.

In use, the metal parts to be welded together, such as for instance theframe 30 and outer panel 31 of an automobile door are first positionedupon the work support as shown in Figure 1, whereupon the usualoperating pedal 33 may be actuated tocause the electrodes 2 and 3 toengage the work. lVhen downwardly so that the electrode 3 will engage areturn-bent ilange 34 of the outer panel and the electrode 2 will engagethe uppermost face of the frame 30, hence the current will flow throughthe frame 30 and flange 34 to effect the welding operation between said'flange and frame.

Heretofore the flange 34 has beeny welded to the frame of the door byelectrodes that were located in substantial alignment above and belowthe door, hence contact of the lower electrode with the outerpanel'would cause the said panel to be dented, scratched or otherwisemarred so that a separate linishing operation, usually in the form of afiling operation, was necessary to remove such disfgurations from theouter panel. However with the present invention there is no Contactwhatever of any of the electrodes with the outer panel, hence the saidpanel cannot be disfigured and such separate fini ishing operations havebeen dispensed with entirely. As a result a considerable saving in time,labor and expense has been effected. Moreover the original exteriorsurface of the panelv has been preserved.

If desired the electrode3 may be cooled by Water which is conveyed toand from the holder 35 of said electrode by suitable conduits 36 and 37respectively, water being free to circulate around the conductor 38within the holder 35 to cool the point 21. Water conduits 39 and 40respectively may also be used to cool the electrical conductors 22 and.

23 respectively. As shown these conduits 39 and 40 surround theconductors 22 and 23 and are terminally secured to short lengths 41 and42 respectively-of pipe that in turn are threadedv into the blockelectrode 2.

' While it is believed that from the foregoing description, the natureand advantage of my invention will be readily apparent. I desire to haveit understood that I do not limit myself to what is herein shown anddescribedA and that such changes may be resorted to when desired as fallwithin the scope of what is claimed.

What I claim asmy invention is e 1. In a welding ap aratus, thecombination with a main frame, o a work support projecting from saidframe and insulated therefrom, a pair of electrodes above said worksupport for engagement with the work, a supporting arm for saidelectrodes pivotally mounted on said frame and insulated therefrom, anelectrical conductor connected to said arm, and an electrical conductorconnected to one of said electrodes, said electrode being insulated fromsaid supporting arm.

2. In a welding apparatus, the combination with a main frame, of a worksupport projecting therefrom, cooperating electrodes movable toward saidsupport to engage the work toetfect a welding operation, a supportingarm for said electrodes pivotally mounted on said fra-me, one of saidelectrodes being rigid- 1y connected to said arm, and the other of saidelectrodes being adjustably connected to said arm.

" 3. In a welding apparatus, the combination with a main frame, of awork support projecting from said frame and insulated therefrom, a pairof electrodes engageable with the work to effect a welding operation, asupporting arm for said electrodes carried by said frame and insulatedtherefrom, one of said electrodes being rigidly secured to said arm, arod connected to the other of said electrodes and adjustably mounted insaid arm, an electrical conductor connected to said arm for supplying acurrent to the rst mentioned electrode, and an electrical conductorconnected to the second mentioned electrode, said rod being insulatedfrom said supporting arm.y 4. In a welding apparatus, the combinationwith a work support, of a'pairfof cooperating electrodes movable towardsaid support to effecta welding operation, one of Said electrodes beingapertured, electrical conductors connected to said apertured electrode,and means for cooling said conductors and aper- `tured electrodeincluding lengths of pipe connected to said apertured electrode, andtubing surrounding said'conductors and connected to said pipes whereby acooling fluid will-flow along said conductors and through said pipesinto the apertured electrode.

5. In a'welding apparatus, the combination with a main frame, and a worksupport projecting from the frame,of an arm pivoted on the frame andmovable toward and from the work Support, a pair of laterally spacedelectrodes carried `by said arm and movable as a unit therewith toengage work on said support, one of said elements being adjustahlyconnected to said arm and normally below the other elcment so that itmay engage the work in advance of the other element and remain in suchengagement while the other element is moving toward the work to closethe circuit thropgh the work laterally to the other clmen 6. In awelding apparatus of the class de` tween the second mentioned electrodeand arm including rod substantially parallel to the with said arm, theother being in the form 10 first-mentioned electrode and movable relaofa plug, and a connection between said plug tive to said arm. and armincluding a rod movable transverse- 7. In a welding apparatus of theclass dely of said arm, and yieldable means on said 5 scribed,tliecombination with a swinging sup-l rod between said arm and plug normallyholdporting arm; of two laterally spaced eleoing said plug and rod inextended position l5 trodes carried by and movable with said larm withrespect to said arm. `to engage one side of the work, one of said Intestimony whereof I atlix my signature. electrodes being pencil-like inform and rigid WILLIAM. I-I. PIERSON.

